Speaker
Description
We consider a dilatonic dyon black hole solution
with a gravitational radius of $2 \mu$ and two charges,
$Q_1$ (electric) and $Q_2$ (magnetic), within the framework
of a four-dimensional gravitational model comprising one scalar field and one 2-form. The dilaton coupling constant $\lambda$ is fixed by $\lambda^2 = \frac{3}{2}$. This solution is related to the $A_2$ Toda chain.
The circular orbits of null geodesics are explored, and the fifth-order polynomial master equation governing the photon sphere radius $R_0$
is analyzed. It is shown to admit a unique solution satisfying $R_0 > 2 \mu$.
The circular null geodesics are proven to be unstable.
Finally, the black hole shadow is examined, yielding relations
for the shadow angle and the critical impact parameter.
